# Instantaneous Velocity

#### cribby

Find the instantaneous velocity of $$\displaystyle sin(2x)$$ at $$\displaystyle x=1$$.

I tried applying the definition of derivative at a point and then using trig identities (double angle, sum), but what I ended up, zero, with didn't make sense. How should this be calculated?

Thanks

f'(x)=m=2cos(2x)

f'(1)=2cos2

#### cribby

Instructor wants me to use the definition of derivative at a point, not a derivative formula.

#### mr fantastic

MHF Hall of Fame
Find the instantaneous velocity of $$\displaystyle sin(2x)$$ at $$\displaystyle x=1$$.

[snip]
That makes no sense. Go back and check the question. Is it meant to be x = sin(2t)?